A three-dimensional model of the human airway tree

A three-dimensional (3D) model of the human airway tree is proposed using a deterministic algorithm that can generate a branching duct system in an or gan. The algorithm is based on two principles: 1) the amount of fluid deliv ery through a branch is proportional to the volume of the region it supplie s; and 2) the terminal branches are arranged homogeneously within the organ . These principles define the basic process of branching: generation of the dimensions and directionality of two daughter branches is governed by the properties of the parent branch and the region the parent supplies. The alg orithm is composed of nine basic rules and four complementary rules. When t he contour of an organ and the position of the trunk are specified, branche s are successively generated by the algorithm. Applied to the human lung, t he algorithm generates an airway tree that consists of similar to 54,000 br anches. Its morphometric characteristics are in good agreement with those r eported in the literature. The algorithm and the 3D airway model are useful for studying the structure-function relationship in the lung.